[TSVB] Disable using top_hits in bucket script aggregations

[kakulukia]

Kibana version: 7.0.1

Elasticsearch version: 7.0.1

Server OS version: CentOS 7

Browser version: Crome Version 75.0.3770.90 (Offizieller Build) (64-Bit)

Browser OS version: Windows Server 2016 Standard

Original install method (e.g. download page, yum, from source, etc.): openstack docker image

Describe the bug:

buckets_path must reference either a number value or a single value numeric metric aggregation, got: org.elasticsearch.search.aggregations.bucket.filter.InternalFilter

This happens while designing a Gauge in the Visual Builder using two TopHit aggregations as a source for two Bucket Script variables.

The bucket script shall only do a simple thing "params.var1 / params.var2" but produces the above error.

Steps to reproduce:

1. Open Visual Builder
2. Create a new Visualisation and switch to Gauge
3. Create to TopHit aggregations of to vars from the same index
4. Add a bucket script using those vars like "params.var1 / params.var2"
5. The preview should now feature the same error as shown above.

Expected behavior:
I dont think i fully understand Elastic/Kibana already and all of its terms, but to my understanding im only using two "single value numeric metric aggregation"s to try to have a dynamic gauge. So this according to some tutorial page i found should give me a working gauge.

[elasticmachine]

Pinging @elastic/kibana-app

[wylieconlon]

I can confirm that this is happening in all the TSVB visualizations, not just Gauge. I'm going to change the title to be more descriptive of what I think is happening here.

[wylieconlon]

[timroes]

@alexwizp It looks like bucket script just doesn't work with Top Hits aggregations together. Maybe we could prevent the params selection in the bucket script to select that kind of aggregations, and instead disable them in the "Variables" view of Bucket Script?

[kakulukia]

That would render me unable to complete my goal of having a dynamic gauge displaying the latest values. Is there an alternative to the bucket script?

[dchoa]

Hi all, do we have a fix on this bug yet?
I meet an issue that may be the same. I'm using time series instead of gause, and it just shows nothing on graph.
I'm using ELK stack version 7.2.
Thanks.

[DeeeFOX]

hi, i'am watching this issue. I want to get the result in a buckets script using: "top_hits[0] - top_hits[1]"

[Erni]

Why there is no Scripted Metric Aggregation in the Aggregation list? I think this would avoid (or reduce) the need of having to use the Top Hits aggregation just for retrieving values to use later in a Bucket Script.

[tylersmalley]

@timroes, do you know if there is a workaround?

[timroes]

Scripted Metric Aggregation doesn't appear in the list, because it's not implemented in TSVB (or any other place in Kibana). You can check a matrix of supported aggregations in #58628 and support for scripted metric aggregations are tracked in #2646.

For clarification: this issue tracks that we make it impossible in the TSVB UI to use top_hits inside the bucket_script aggregation, because they do not work from Elasticsearch side.